Inspection apparatus, inspection method, and recording medium

Abstract

The invention relates to an inspection apparatus, an inspection method, and a recording medium, and provides an inspection apparatus capable of inspecting a repeated structure of a workpiece by photographing the view direction of a line sensor at a substantially integer ratio without changing the magnification of an image pickup system. An inspection device (1) for inspecting a workpiece (2) having a repeating structure is provided with: a stage (10); a line sensor (20) that captures an image of the workpiece (2) placed on the stage (10), the field-of-view direction being a first direction; and a calculation unit (51) that calculates an imaging condition of the workpiece (2). A calculation unit (51) calculates Ry and [theta] using Rx (resolution of imaging in a first direction), Ta (cycle of one repetition of a repetition structure), and Tb (cycle of another repetition of the repetition structure) as input parameters, and an inspection device (1) rotates a workpiece (2) so as to be at an angle of [theta], thereby causing a line sensor (20) to scan in a state in which the workpiece (2) is tilted, and imaging the workpiece (2).

Description

Technical Field

[0001] The present disclosure relates to an inspection device, an inspection method, and a recording medium having a program recorded thereon for inspecting a workpiece having a repetitive structure. Background Art

[0002] It is known to inspect defects in workpieces having a repetitive structure (repetitive pattern). For example, a substrate in a display device such as a liquid crystal display panel or an organic EL panel, a solar cell, or an imaging device, etc., is provided with a plurality of transistors as a repetitive structure that is repeatedly arranged in two orthogonal directions.

[0003] Conventionally, as a method for inspecting defects of a workpiece having such a repetitive structure, the following technology is known, that is, placing a workpiece having a repetitive structure as an object to be inspected on a stage, causing a line sensor (camera) to scan the object to be inspected to take an image of the object to be inspected, and processing the image to inspect whether the repetitive structure has defects. In this case, in the image of the object to be inspected, by performing a comparative inspection on a comparison base pixel and a comparison target pixel existing at a position separated by a repetitive spacing amount, a portion of the image that does not satisfy the periodicity of the repetitive structure can be detected.

[0004] However, the repetitive pitch of the repetitive structure in the inspected object is not necessarily an integer ratio (integer multiple) to the imaging resolution of the line sensor. In this case, the pixels of the repetitive structure of the comparison basis cannot be compared with the pixels of the repetitive structure of the correct comparison object, so the inspection accuracy is reduced.

[0005] Therefore, in an inspection method for inspecting defects in a repeated structure of an object by photographing the object with a camera through a lens, a technique has been proposed in which the lens is provided with a zoom mechanism to adjust the magnification to a suitable value for the object to be inspected (Patent Document 1).

[0006] Prior Art Literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent No. 4165115 Summary of the invention

[0009] Problems to be solved by the invention

[0010] However, the inspection method disclosed in Patent Document 1 has a problem that the magnification of the lens can be adjusted only in the field of view direction of the line sensor (a direction orthogonal to the scanning direction).

[0011] The present disclosure is to solve such a problem, and an object of the present disclosure is to provide an inspection device and an inspection method that can inspect a repetitive structure of a workpiece by imaging the field of view direction of a line sensor at a substantially integer ratio without changing the magnification of an imaging system.

[0012] Means for solving problems

[0013] In order to achieve the above-mentioned purpose, one mode of the inspection device involved in the present disclosure is an inspection device for inspecting a workpiece having a repeated structure repeatedly arranged in two orthogonal directions, the inspection device comprising: a stage; a line sensor with a field of view in a first direction for photographing the workpiece placed on the stage; a rotation drive mechanism for rotating the workpiece so that it forms a given angle with a second direction orthogonal to the first direction; and a calculation unit for calculating the imaging conditions of the workpiece. If the resolution of the imaging in the first direction in the inspection device is set to Rx, and the resolution of the imaging in the second direction in the inspection device is set to Ry, The given angle is set as θ, the repetition period of the repetitive structure in one of the two orthogonal directions in the workpiece is set as Ta, and the repetition period of the repetitive structure in the other of the two orthogonal directions in the workpiece is set as Tb, then the operation unit uses Rx, Ta and Tb as input parameters, calculates Ry and θ as the shooting condition, and the inspection device rotates the workpiece through the rotation drive mechanism to make it become the angle of θ calculated by the operation unit, so that the line sensor is scanned while the workpiece is tilted to shoot the workpiece.

[0014] In addition, one mode of the inspection method involved in the present disclosure is an inspection method for inspecting a workpiece having a repeated structure repeatedly arranged in two orthogonal directions, the inspection method comprising: a calculation step of calculating a given imaging condition; a rotation step of rotating and tilting the workpiece based on the imaging condition so as to form a given angle with a second direction orthogonal to the first direction; an imaging step of scanning the workpiece along the second direction with a line sensor having a field of view direction in the first direction; and an inspection step of inspecting the repeated structure of the workpiece based on the imaging image of the workpiece captured by the line sensor. If the resolution of the imaging in the first direction is The rate is set to Rx, the resolution of the imaging in the second direction is set to Ry, the given angle is set to θ, the repetition period of the repetitive structure in one of the two orthogonal directions in the workpiece is set to Ta, and the repetition period of the repetitive structure in the other of the two orthogonal directions in the workpiece is set to Tb. In the calculation step, Rx, Ta and Tb are used as input parameters, and Ry and θ are calculated as the imaging conditions. In the imaging step, the line sensor is scanned in a state where the workpiece is tilted at an angle of θ calculated by the calculation step, so as to image the workpiece.

[0015] In addition, one mode of the recording medium involved in the present disclosure is a recording medium having recorded thereon a program used in an inspection method, wherein the inspection method inspects a workpiece having a repeated structure repeatedly arranged in two orthogonal directions, the inspection method comprising: a calculation step of calculating a given imaging condition; a rotation step of rotating and tilting the workpiece based on the imaging condition so as to form a given angle with a second direction orthogonal to the first direction; an imaging step of causing a line sensor having a field of view direction in the first direction to scan along the second direction to image the workpiece; and an inspection step of inspecting the repeated structure of the workpiece based on an image of the workpiece captured by the line sensor. If the resolution of the imaging in the first direction is set to is Rx, the resolution of the imaging in the second direction is Ry, the given angle is θ, the repetition period of the repetitive structure in one of the two orthogonal directions in the workpiece is Ta, and the repetition period of the repetitive structure in the other of the two orthogonal directions in the workpiece is Tb. In the calculation step, Rx, Ta and Tb are used as input parameters, and Ry and θ are calculated as the imaging conditions. In the imaging step, the line sensor is scanned in a state where the workpiece is tilted at an angle of θ calculated by the calculation step, so as to image the workpiece. The program is a program for causing the processor to execute the calculation step.

[0016] Effects of the Invention

[0017] According to the present disclosure, it is possible to inspect the repetitive structure of a workpiece by imaging the field of view direction of the line sensor at a substantially integer ratio without changing the magnification of the imaging system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a diagram showing the structure of an inspection device for inspecting a workpiece having a repetitive structure.

[0019] Figure 2 This is a diagram for explaining the repetitive pitch of the repetitive structure of a workpiece.

[0020] Figure 3 This is a diagram showing an example of a residual error when image processing is performed on a captured image when a defect in a repeated structure of a workpiece is determined without tilting the workpiece.

[0021] Figure 4 This is a diagram for explaining the principle of inspecting a workpiece using the inspection device according to the embodiment.

[0022] Figure 5 This is a diagram for explaining the repetitive pitch of the repetitive structure of the workpiece when the workpiece is tilted.

[0023] Figure 6 This is a diagram showing an example of a residual error when image processing is performed on a captured image when a defect in a repeated structure of a workpiece is determined while the workpiece is tilted.

[0024] Figure 7 It is a diagram showing the structure of an inspection device according to an embodiment.

[0025] Figure 8 This is a block diagram of an inspection device according to an embodiment.

[0026] Fig. 9 It is a flowchart of the inspection method involved in the embodiment.

[0027] Fig.10 It is a diagram showing simulation results when the inspection method according to the embodiment is performed using scanning ARS in combination.

[0028] Fig.11 It is a diagram showing simulation results when the inspection method according to the embodiment is performed without using the scanning ARS in combination.

[0029] Fig.12 It is a diagram showing simulation results when the inspection method according to the embodiment is performed using an area sensor instead of a line sensor.

[0030] Fig.13 Yes Figure 10 to Figure 12The numerical simulation results are shown in Figure 2.

[0031] Explanation of symbols

[0032] 1 Inspection device

[0033] 2 Workpiece

[0034] 10. Stage

[0035] 20-wire sensor

[0036] 20a Camera area

[0037] 30 Rotation drive mechanism

[0038] 40 Linear drive mechanism

[0039] 50 Processing device

[0040] 51 Operation unit

[0041] 52. Drive control unit

[0042] 53 Image Processing Unit DETAILED DESCRIPTION

[0043] (How one method of the present disclosure was obtained)

[0044] Before describing the embodiments of the present disclosure, a process of arriving at one embodiment of the present disclosure will be described.

[0045] First, use Figure 1 as well as Figure 2 A conventional inspection method for inspecting defects of a workpiece 2 having a repetitive structure will be described. Figure 1 1 is a diagram showing a configuration of an inspection device 1X for inspecting a workpiece 2 having a repetitive structure. Figure 2 FIG. 2 is a diagram for explaining the repetitive pitch of the repetitive structure of the workpiece 2, schematically showing Figure 1 An enlarged view of a region A surrounded by a single-point dashed line in a workpiece 2. In addition, in this specification and the drawings, the X-axis, the Y-axis, and the Z-axis represent three axes of a three-dimensional orthogonal coordinate system. The X-axis and the Y-axis are axes that are orthogonal to each other and are both orthogonal to the Z-axis. In this embodiment, the Z-axis direction is the vertical direction.

[0046] like Figure 1 As shown, the inspection device 1X includes a stage 10 on which a workpiece 2 is placed, and a line sensor 20 for capturing an image of the workpiece 2. In the inspection device 1X, the field of view direction of the line sensor 20 is the X-axis direction. Therefore, a primary imaging area 20a of the line sensor 20 extends along the X-axis direction. In addition, the scanning direction of the line sensor 20 is the Y-axis direction.

[0047] exist Figure 2 In FIG. 1 , the black dots indicate the locations of the repeated structures of workpiece 2. Figure 2 As shown, the repeated structure of the workpiece 2 is repeatedly present in the a direction and the b direction, which are two orthogonal directions, at a fixed period (pitch). The a direction is one of the two orthogonal directions, and the b direction is the other of the two orthogonal directions. The repeated period (repeating pitch) of the a direction is Ta, and the repeated period (repeating pitch) of the b direction is Tb, and the repeated structure of the workpiece 2 is repeatedly set in the a direction and the b direction.

[0048] When the inspection device 1X is used to inspect the workpiece 2 having such a repeated structure, first, Figure 1 As shown in FIG. 1 , a workpiece 2 as an object to be inspected is placed on a stage 10. Figure 2 As shown, the workpiece 2 is placed so that the a direction in the repeated structure is consistent with the X-axis direction and the b direction is consistent with the Y-axis direction. That is, the workpiece 2 is placed on the stage 10 so that the multiple repeated structures are repeatedly present along the X-axis direction and the Y-axis direction. Therefore, the workpiece 2 is placed so that the repeated directions of the multiple repeated structures are consistent with the field of view direction and scanning direction of the line sensor 20.

[0049] Then, when inspecting the repeated structure of the workpiece 2, the line sensor 20 is made to scan the workpiece 2 placed on the stage 10 along the scanning direction (Y-axis direction), thereby capturing an image of the entire workpiece 2, and judging whether the repeated structure of the workpiece 2 has defects based on the captured image. In other words, image processing is performed based on the captured image to judge whether the repeated structure of the workpiece 2 has defects.

[0050] Specifically, in the image of the workpiece 2 captured by the line sensor 20, a portion that does not satisfy the periodicity of the repeated structure is determined as a defect by performing a comparative inspection, in which the concentration of the pixels of the repeated structure of the comparison basis is compared with the concentration of the pixels of the repeated structure of the comparison object existing at a position separated by a spacing amount of an integer multiple of the repeated spacing. For example, the difference between the concentration of the pixels of the repeated structure of the comparison basis and the concentration of the pixels of the repeated structure of the comparison object existing at a position separated by a spacing amount of an integer multiple of the repeated spacing of the repeated structure is calculated, and when the concentration value of the difference is above a given first threshold value or below a given second threshold value, the portion that does not satisfy the periodicity of the repeated structure is determined as a defect. An example of such image processing is described below.

[0051] If the vectors of the two actual repetitive structures to be compared in the workpiece 2 are (Xa, Ya) and the vectors of the two repetitive structures on the image captured by the line sensor 20 are (Xp, Yp), (Xa, Ya) is expressed by the following (Formula 1).

[0052] (Xa, Ya)=(Cx×Xp, Cy×Yp) (Formula 1)

[0053] In (Formula 1), Cx=0, ±1, ±2, ..., Cy=0, ±1, ±2, ...

[0054] Here, (Xa, Ya) is a vector indicating the distance between the repeated structure P1 as a comparison basis and the repeated structure P1 as a comparison target in two actual repeated structures. Also, (Xp, Yp) is a vector indicating the distance between the repeated structure P1 as a comparison basis and the repeated structure P1 as a comparison target in two repeated structures on an image captured by the line sensor 20.

[0055] In addition, Figure 2 In the figure, the repeated structures P1 and P2 are shown when Cx=1 and Cy=1 in (Equation 1). Figure 2 In , the repetitive structure P2 to be compared exists at a position separated from the repetitive structure P1 to be compared by one pitch in the a direction and the b direction.

[0056] In this case, if the imaging resolution of the line sensor 20 in the X-axis direction is set to Rx, and the imaging resolution of the line sensor 20 in the Y-axis direction is set to Ry, then the vector (Xp, Yp) representing the distance between the repeated structure P1 and the repeated structure P2 on the image captured by the line sensor 20 is expressed by the following (Formula 2), where the unit is set to "pixel".

[0057] (Xp, Yp) = (Ta / Rx, Tb / Ry) (Formula 2)

[0058] At this time, since the image processing for determining defects is performed in units of pixels, there will be residual errors if (Xp, Yp) is not an integer. For example, if the target repetition period (repetition pitch) Ta and Tb are set to Ta = 1232μm, Tb = 987μm, and the image resolution Rx and Ry of the line sensor 20 are set to Rx = 5μm / pix, Ry = 5μm / pix, and an attempt is made to calculate the residual errors within the range of Cx and Cy ±1, then Figure 3 As shown in FIG. 1 , the maximum value (worst value) of the remaining error is 0.400 pixels. That is, the repetitive pitch of the repetitive structure in the workpiece 2 and the imaging resolution of the line sensor 20 do not form an integer ratio.

[0059] Thus, the repetitive pitch of the repetitive structure in the workpiece 2 is not necessarily an integer ratio to the resolution of the image captured by the line sensor 20. In this case, in the image captured by the workpiece 2, since the number of pixels from the pixels of the repetitive structure P1 as a comparison basis to the pixels of the repetitive structure P2 as a comparison target is not an integer, the pixels of the repetitive structure P1 as a comparison basis cannot be compared with the pixels of the repetitive structure P2 as a comparison target, and the inspection accuracy is reduced.

[0060] To this end, as disclosed in Patent Document 1, a method is considered in which the magnification of the imaging system is changed using a lens so that the number of pixels from the pixels of the comparison base repetitive structure P1 to the pixels of the comparison target repetitive structure P2 in the image of the workpiece 2 is an integer.

[0061] However, in this method, only the field of view direction of the line sensor 20 (direction orthogonal to the scanning direction: Figure 1 In addition, in this method, since a mechanical drive unit is required to zoom the lens, the reproducibility of the action when adjusting the magnification of the lens is poor, and the adjustment accuracy of the lens is low. Moreover, if a mechanical drive unit is used to zoom the lens, the inspection device becomes large.

[0062] Therefore, as a result of intensive studies on such a subject, the inventors of the present application have found that the above-mentioned Xp can be made an integer by tilting the workpiece 2 for imaging.

[0063] Specifically, Figure 4 As shown, the workpiece 2 is rotated at an angle of θ to tilt the workpiece 2. In addition, Figure 4 The figure shows the situation when the workpiece 2 is inspected while the workpiece 2 is tilted. Figure 5 Schematically Figure 4 An enlarged view of a region A surrounded by a single-dot chain line in the workpiece 2.

[0064] like Figure 5 As shown, by inclining the workpiece 2 at an angle of θ, the a direction and the b direction, which are the repeating directions of the workpiece 2, are also inclined at an angle of θ. Specifically, the angle formed by the b direction and the Y-axis direction is θ.

[0065] Therefore, when the workpiece 2 is tilted and imaged by the line sensor 20, the image is captured such that the repetitive pitch of the repetitive structure in the field of view direction (X-axis direction) of the line sensor 20 is substantially reduced, and the repetitive pitch of the repetitive structure in the scanning direction (Y-axis direction) of the line sensor 20 is substantially increased. As a result, the workpiece 2 can be imaged so that the number of pixels from the pixels of the repetitive structure P1 as a comparison basis to the pixels of the repetitive structure P2 as a comparison target is as integer as possible. This point will be described below.

[0066] In the image captured by rotating the workpiece 2, the vector also rotates. Therefore, the vector (Xn, Yn) obtained when the two repetitive structure vectors (Xa, Ya) to be compared represented by (Formula 1) are rotated by an angle of θ is represented by the following (Formula 3).

[0067] (Xn, Yn)=(Xa×cosθ-Ya×sinθ, Xa×sinθ+Ya×cosθ) (Formula 3)

[0068] Furthermore, based on (Formula 2) and (Formula 3), it can be seen that the above-mentioned error can be reduced by trying to select θ and Ry so that the two repetitively constructed vectors (Xp, Yp) on the image captured by the line sensor 20 are integers as much as possible. In addition, since the resolution Rx in the X-axis direction is an inherent value of the inspection device (line sensor 20), and Ta and Tb are inherent values ​​of the workpiece 2, there is no freedom of choice for Rx, Ta, and Tb. On the other hand, if the scanning ARS described later is considered, there is freedom of choice for Ry. Therefore, θ and Ry were explored.

[0069] Specifically, if, as described above, the target repetition period (repetition pitch) Ta and Tb are set to Ta = 1232 μm, Tb = 987 μm, and the image resolution Rx of the line sensor 20 is set to Rx = 5 μm / pix, θ and Ry are selected to be θ = 3.195°, Ry = 4.903 μm / pix, and an attempt is made to calculate the residual error within the range of Cx and Cy being ±1, then Figure 6 As shown, the maximum value (worst value) of the residual error can be reduced to 0.019 pixels. That is, the repetition pitch of the repetitive structure in the workpiece 2 and the imaging resolution of the line sensor 20 can be made to be a substantially integer ratio.

[0070] Thus, the inventors of the present application found that by tilting the workpiece 2 , the field of view direction (X-axis direction) of the line sensor 20 can be imaged at a substantially integer ratio, thereby obtaining one aspect of the inspection device and inspection method disclosed herein.

[0071] Specifically, one mode of the inspection device involved in the present disclosure is an inspection device for inspecting a workpiece having a repeated structure repeatedly arranged in two orthogonal directions, the inspection device comprising: a stage; a line sensor, the field of view direction of which is a first direction, for photographing the workpiece placed on the stage; a rotation drive mechanism, for rotating the workpiece so that it forms a given angle with a second direction orthogonal to the first direction; and a calculation unit, for calculating the imaging conditions of the workpiece. If the resolution of the imaging in the first direction in the inspection device is set to Rx, and the resolution of the imaging in the second direction in the inspection device is set to Ry, the imaging conditions of the workpiece are calculated. The given angle is set as θ, the repetition period of the repetitive structure in one of the two orthogonal directions in the workpiece is set as Ta, and the repetition period of the repetitive structure in the other of the two orthogonal directions in the workpiece is set as Tb, then the calculation unit uses Rx, Ta and Tb as input parameters, calculates Ry and θ as the shooting condition, and the inspection device rotates the workpiece through the rotation drive mechanism to make it become the angle of θ calculated by the calculation unit, so that the line sensor is scanned to shoot the workpiece while the workpiece is tilted.

[0072] With this configuration, it is possible to capture images in the field of view direction of the line sensor at a substantially integer ratio without changing the magnification of the imaging system. Therefore, it is possible to inspect the repetitive structure of the workpiece with high accuracy.

[0073] In this case, in one aspect of the inspection device according to the present disclosure, it is preferable that the inspection device inspects defects of the workpiece by comparing pixels of two of the repeated structures in a captured image of the workpiece acquired by scanning the line sensor.

[0074] With this configuration, it is possible to detect defects in the workpiece by scanning the line sensor to capture an image of the workpiece and comparing pixels of two repetitive structures in the obtained captured image.

[0075] Furthermore, in one mode of the inspection device involved in the present disclosure, it is preferred that if the two vectors of the repeated structures in the state before the workpiece is tilted at an angle of θ are set to (Xa, Ya), the two vectors of the repeated structures in the state after the workpiece is tilted at an angle of θ are set to (Xn, Yn), and the two vectors of the repeated structures on the camera image are set to (Xp, Yp), then Xp and Yp are expressed by the following formulas: Xp=Xn / Rx=(Xa×cosθ-Ya×sinθ) / Rx, Yp=Yn / Ry=(Xa×sinθ+Ya×cosθ) / Ry, and the calculation unit calculates θ and Ry so that Xp and Yp are integers.

[0076] In this way, by calculating θ and Ry so that Xp and Yp are integers, it is possible to capture images in the field of view direction of the line sensor at an integer ratio.

[0077] Furthermore, in one aspect of the inspection device according to the present disclosure, it is preferable that the calculation unit calculates Ry and θ by changing Ry so that Yp becomes an integer period on the captured image.

[0078] This allows not only the field of view direction of the line sensor but also the scanning direction of the line sensor to be imaged at a substantially integer ratio. Therefore, it is possible to inspect the repetitive structure of the workpiece with higher accuracy.

[0079] In addition, one mode of the inspection method involved in the present disclosure is an inspection method for inspecting a workpiece having a repeated structure repeatedly arranged in two orthogonal directions, the inspection method comprising: a calculation step of calculating a given imaging condition; a rotation step of rotating and tilting the workpiece based on the imaging condition so as to form a given angle with a second direction orthogonal to the first direction; an imaging step of scanning the workpiece along the second direction with a line sensor having a field of view direction in the first direction; and an inspection step of inspecting the repeated structure of the workpiece based on the imaging image of the workpiece captured by the line sensor. If the resolution of the imaging in the first direction is The rate is set to Rx, the resolution of the imaging in the second direction is set to Ry, the given angle is set to θ, the repetition period of the repetitive structure in one of the two orthogonal directions in the workpiece is set to Ta, and the repetition period of the repetitive structure in the other of the two orthogonal directions in the workpiece is set to Tb. In the calculation step, Rx, Ta and Tb are used as input parameters, and Ry and θ are calculated as the imaging conditions. In the imaging step, the line sensor is scanned in a state where the workpiece is tilted at an angle of θ calculated by the calculation step, so as to image the workpiece.

[0080] This makes it possible to capture images in the field of view direction of the line sensor at a substantially integer ratio without changing the magnification of the imaging system. Therefore, it is possible to inspect the repetitive structure of the workpiece with high accuracy.

[0081] In this case, in one aspect of the inspection method according to the present disclosure, it is preferable that in the inspection step, two pixels of the repeated structure in the captured image of the workpiece are compared to inspect defects of the workpiece.

[0082] Thus, defects of the workpiece can be inspected by scanning the line sensor to capture an image of the workpiece and comparing pixels of two repetitive structures in the obtained captured image.

[0083] Furthermore, in one embodiment of the inspection method involved in the present disclosure, it is preferred that if the two vectors of the repeated structures in the state before the workpiece is tilted at an angle of θ are set to (Xa, Ya), the two vectors of the repeated structures in the state after the workpiece is tilted at an angle of θ are set to (Xn, Yn), and the two vectors of the repeated structures on the camera image are set to (Xp, Yp), then Xp and Yp are expressed by the following formulas: Xp=Xn / Rx=(Xa×cosθ-Ya×sinθ) / Rx, Yp=Yn / Ry=(Xa×sinθ+Ya×cosθ) / Ry, and in the calculation step, θ and Ry are calculated so that Xp and Yp are integers.

[0084] In this way, by calculating θ and Ry so that Xp and Yp are integers, it is possible to capture images in the field of view direction of the line sensor at an integer ratio.

[0085] Furthermore, in one aspect of the inspection method according to the present disclosure, it is preferable that, in the calculation step, Ry and θ are calculated by changing Ry so that Tb becomes an integer period on the captured image.

[0086] This allows not only the field of view direction of the line sensor but also the scanning direction of the line sensor to be imaged at a substantially integer ratio. Therefore, it is possible to inspect the repetitive structure of the workpiece with higher accuracy.

[0087] In addition, the technology disclosed in the present invention can also be used as a program. Specifically, one form of the program involved in the present invention is a program used in an inspection method, which inspects a workpiece having a repeated structure repeatedly arranged in two orthogonal directions, and the inspection method includes: a calculation step, calculating a given imaging condition; a rotation step, based on the imaging condition, rotating and tilting the workpiece so as to form a given angle with a second direction orthogonal to the first direction; an imaging step, causing a line sensor whose field of view direction is the first direction to scan along the second direction to image the workpiece; and an inspection step, based on the camera image of the workpiece captured by the line sensor, inspecting the repeated structure of the workpiece, if the resolution of the imaging in the first direction is set to Rx, The resolution of the camera in the second direction is set to Ry, the given angle is set to θ, the repetition period of the repeated structure in one of the two orthogonal directions in the workpiece is set to Ta, and the repetition period of the repeated structure in the other of the two orthogonal directions in the workpiece is set to Tb. In the calculation step, Rx, Ta and Tb are used as input parameters, and Ry and θ are calculated as the camera conditions. In the camera step, the line sensor is scanned in a state where the workpiece is tilted at an angle of θ calculated by the calculation step, so as to image the workpiece. The program is a program for causing the processor to execute the calculation step.

[0088] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the embodiments described below all represent a specific example of the present invention. Therefore, the numerical values, shapes, materials, structural elements, configuration positions of structural elements, and connection methods shown in the following embodiments are examples and are not intended to limit the present invention. Therefore, for the structural elements in the following embodiments that are not recorded in the independent technical solutions representing the highest concept of the present invention, they are described as arbitrary structural elements.

[0089] In addition, each figure is a schematic diagram and may not be strictly illustrated. In addition, in each figure, the same symbols are given to substantially the same structure, and repeated descriptions are omitted or simplified. In addition, in this specification, the terms "upper" and "lower" do not necessarily refer to the upper direction (vertically above) and the lower direction (vertically below) in absolute spatial recognition.

[0090] (Implementation Method)

[0091] First, refer to Figure 4 as well as Figure 5 and use Figure 7 as well as Figure 8 , the structure of the inspection device 1 involved in the embodiment of the present disclosure is described. Figure 7 It is a diagram showing the structure of the inspection device 1 according to the embodiment. Figure 8 It is a block diagram of the inspection device 1 according to the embodiment.

[0092] The inspection device 1 is an inspection device that inspects a workpiece 2 having a repeated structure repeatedly provided in two orthogonal directions.

[0093] The workpiece 2 is an object to be inspected (inspection target object) by the inspection device 1. Figure 5 As shown, the repeated structure of the workpiece 2 is repeatedly present in the a direction and the b direction, which are two orthogonal directions, at a fixed period (pitch). The a direction is one of the two orthogonal directions, and the b direction is the other of the two orthogonal directions. The repeated period (repeating pitch) of the a direction is Ta, and the repeated period (repeating pitch) of the b direction is Tb, and the repeated structure of the workpiece 2 is repeatedly set in the a direction and the b direction.

[0094] The workpiece 2 is, for example, a substrate in a liquid crystal display panel or the like. In this case, a plurality of transistors or the like are provided on the substrate as the workpiece 2, for example, as a repeated structure (repeated pattern) repeatedly provided in two orthogonal directions. For example, the plurality of transistors are repeatedly provided in the row direction (b direction) and the column direction (a direction) at a fixed pitch (period).

[0095] like Figure 7 as well as Figure 8 As shown, the inspection device 1 includes a stage 10 , a line sensor 20 , a rotation drive mechanism 30 , a linear drive mechanism 40 , and a processing device 50 .

[0096] The stage 10 is a stage on which the workpiece 2 as the object to be inspected is placed. The stage 10 has a planar placement surface on which the workpiece 2 is placed. The placement surface is parallel to the XY plane. In addition, the stage 10 can also be configured to be able to move independently in the X-axis direction, the Y-axis direction, and the Z-axis direction.

[0097] The line sensor 20 is a camera that captures the workpiece 2 placed on the stage 10. In the present embodiment, the first direction, which is the field of view of the line sensor 20, is the X-axis direction. The primary imaging area 20a of the line sensor 20 is an area extending in a straight strip along the X-axis direction. In addition, the scanning direction of the line sensor 20 is the Y-axis direction.

[0098] The rotation drive mechanism 30 has a drive device that rotates the workpiece 2 so as to form a given angle with a second direction that is orthogonal to the first direction, and the first direction is the field of view direction of the line sensor 20. In this embodiment, since the field of view direction (first direction) of the line sensor 20 is the X-axis direction, the second direction orthogonal to the first direction is the Y-axis direction. Therefore, the rotation drive mechanism 30 rotates the workpiece 2 so as to form a given angle with the Y-axis direction.

[0099] Specifically, the rotation drive mechanism 30 has a drive device that rotates the stage 10 so as to form a given angle with respect to the Y-axis direction. In other words, the stage 10 is rotated by the rotation drive mechanism 30, so that the workpiece 2 placed on the stage 10 rotates and tilts at a given angle relative to the Y-axis direction.

[0100] For example, Figure 4 as well as Figure 5 As shown in FIG. 1 , if the stage 10 is rotated by the rotation drive mechanism 30 so that the angle formed with the Y-axis direction is θ, the workpiece 2 is inclined with respect to the Y-axis direction at the angle θ. That is, in the repeated structure of the workpiece 2, the angle formed between the a-direction and the b-direction (the direction repeated at the repetition pitch of the period Tb) and the Y-axis direction is the angle θ.

[0101] In addition, in the present embodiment, the workpiece 2 is tilted by rotating the stage 10, but the present invention is not limited thereto. For example, the workpiece 2 may be tilted without rotating the stage 10. In this case, the rotation drive mechanism 30 has a drive device that only rotates the workpiece 2 disposed on the stage 10.

[0102] The linear drive mechanism 40 is a drive device that causes the line sensor 20 to scan along a second direction (scanning direction) that is orthogonal to the first direction that is the field of view direction of the line sensor 20. The linear drive mechanism 40 is composed of, for example, a scanning axis that supports the line sensor 20 and moves along the scanning direction, and a linear encoder that detects the position of the scanning axis. The linear encoder outputs a signal every time the scanning axis moves a fixed distance. Thus, the position of the line sensor 20 supported by the scanning axis (that is, the moving distance of the line sensor 20 in the scanning direction) can be grasped.

[0103] The processing device 50 includes a computing unit 51, a drive control unit 52, and an image processing unit 53. The processing device 50 may also include a storage unit such as a memory. The processing device 50 may be a terminal device installed near the stage 10 or a remote device such as a server.

[0104] When inspecting the workpiece 2, the calculation unit 51 calculates the imaging conditions of the workpiece 2 in advance. Specifically, if the imaging resolution in the first direction in the inspection device 1 (in this embodiment, the imaging resolution in the field of view direction of the line sensor 20) is set to Rx, the imaging resolution in the second direction in the inspection device 1 (in this embodiment, the imaging resolution in the scanning direction of the line sensor 20) is set to Ry, the given angle when the workpiece 2 is tilted is set to θ, the repetition period of the repetitive structure in one of the two orthogonal directions in the workpiece 2 (in this embodiment, the a direction) is set to Ta, and the repetition period of the repetitive structure in the other of the two orthogonal directions in the workpiece 2 (in this embodiment, the b direction) is set to Tb, the calculation unit 51 uses Rx, Ta, and Tb as input parameters, and calculates Ry and θ as imaging conditions.

[0105] In this embodiment, the calculation unit 51 changes Ry so that the repetition period Tb of the repetitive structure becomes an integer period on the camera image, thereby calculating Ry and θ. That is, the calculation unit 51 changes the resolution Ry, which is the imaging resolution in the scanning direction (scan direction) of the line sensor 20, to calculate Ry and θ. Such a method is called scanning ARS (Adaptive Resolution System), and is disclosed in Japanese Patent No. 5417997.

[0106] The drive control unit 52 drives the rotation drive mechanism 30 according to θ calculated by the calculation unit 51. Specifically, before the workpiece 2 is imaged, the rotation drive mechanism 30 rotates the stage 10 according to the angle θ sent from the drive control unit 52, thereby tilting the workpiece 2. In addition, the drive control unit 52 drives the linear drive mechanism 40 to scan the line sensor 20. That is, the workpiece 2 is imaged by scanning the line sensor 20 through the drive control unit 52.

[0107] The image processing unit 53 performs image processing based on the image captured by the line sensor 20, thereby determining whether the repeated structure of the workpiece 2 has defects. At this time, the image processing unit 53 determines whether the repeated structure of the workpiece 2 has defects based on the resolution Rx and the resolution Ry calculated by the operation unit 51. Specifically, in the image of the workpiece 2 captured by the line sensor 20, a portion that does not satisfy the periodicity of the repeated structure is determined as a defect by performing a comparative inspection, which compares the density of the pixel of the repeated structure of the comparison basis with the density of the pixel of the repeated structure of the comparison object existing at a position separated by a pitch amount of an integer multiple of the repeated pitch. For example, the difference between the density of the pixel of the repeated structure of the comparison basis and the density of the pixel of the repeated structure of the comparison object existing at a position separated by a pitch amount of an integer multiple of the repeated pitch of the repeated structure is calculated, and when the density value of the difference is greater than a given first threshold value or less than a given second threshold value, the portion that does not satisfy the periodicity of the repeated structure is determined as a defect.

[0108] In addition, the operation unit 51, the drive control unit 52 and the image processing unit 53 are composed of, for example, a processor or a circuit. In this case, the operation unit 51, the drive control unit 52 and the image processing unit 53 can be composed of separate processors or circuits, or can be composed of one processor or circuit as a whole. In addition, the processing device 50 having the operation unit 51, the drive control unit 52 and the image processing unit 53 can also be composed of an information processing device such as a computer. In this case, the processing described as the action of the processing device 50 of the operation unit 51 and the like is performed by a computer. For example, the computer can execute the above-mentioned processing by using hardware resources such as a processor (CPU), a memory and an input / output circuit to execute a program. The results of each processing can also be stored in a memory (not shown) in the processing device 50.

[0109] Next, refer to Figure 4 as well as Figure 5 and use Fig. 9 , a method for inspecting a workpiece 2 using the inspection device 1 is described. Fig. 9 It is a flowchart of the inspection method involved in the embodiment.

[0110] like Fig. 9 As shown, the inspection method involved in this embodiment is an inspection method for inspecting a workpiece 2 having a repeated structure repeatedly arranged in two orthogonal directions, and includes a calculation step S1, a rotation step S2, a camera step S3, and an inspection step S4.

[0111] The calculation step S1 is a step of calculating and calculating a given imaging condition by the calculation unit 51. That is, the calculation step S1 is an imaging condition calculation step of calculating the imaging condition in advance before the line sensor 20 images the workpiece 2. In the present embodiment, since the workpiece 2 is rotated to tilt the workpiece 2 relative to the scanning direction of the line sensor 20, the imaging condition including the angle θ as the rotation angle for rotating the workpiece 2 is calculated in the calculation step S1.

[0112] Specifically, if the imaging resolution in the field of view direction of the line sensor 20 is set to Rx, the imaging resolution in the scanning direction of the line sensor 20 is set to Ry, the given angle when the workpiece 2 is tilted is set to θ, the repetition period in the a direction of the repeated structure of the workpiece 2 is set to Ta, and the repetition period in the b direction of the repeated structure of the workpiece 2 is set to Tb, then in the calculation step S1, Rx, Ta and Tb are used as input parameters, and Ry and θ are calculated as imaging conditions.

[0113] More specifically, Ry and θ are calculated as follows. In the present embodiment, since the workpiece 2 is imaged while being tilted relative to the scanning direction of the line sensor 20, if the vectors of the two repeated structures in the state before the workpiece 2 is tilted at an angle of θ are set to (Xa, Ya), the vectors of the two repeated structures in the state after the workpiece 2 is tilted at an angle of θ are set to (Xn, Yn), and the vectors of the two repeated structures on the image captured by the line sensor 20 are set to (Xp, Yp), then in the calculation step S1, θ and Ry are calculated so that Xp and Yp are integers. That is, a combination of θ and Ry that makes Xp and Yp integers is searched. In addition, Xp and Yp are represented by the following (Formula 4) and (Formula 5).

[0114] Xp=Xn / Rx=(Xa×cosθ-Ya×sinθ) / Rx (Formula 4)

[0115] Yp=Yn / Ry=(Xa×sinθ+Ya×cosθ) / Ry (Formula 5)

[0116] In addition, in the present embodiment, Ry and θ are calculated by scanning the ARS as described above. That is, in the calculation step S1, the resolution Ry, which is the imaging resolution in the scanning direction (scan direction) of the line sensor 20, is changed so that the repetition period Tb of the repetition structure becomes an integer period on the imaging image, thereby calculating Ry and θ.

[0117] Note that the calculation step S1 may be performed after the workpiece 2 is placed on the stage 10 of the inspection apparatus 1 , or may be performed before the workpiece 2 is placed on the stage 10 .

[0118] The rotating step S2 is a step of rotating the workpiece 2 to be inspected. Therefore, the rotating step S2 is performed after the workpiece 2 to be inspected is placed on the stage 10 .

[0119] In the rotating step S2, based on the imaging conditions calculated in the computing step S1, the workpiece 2 is rotated and tilted so as to form a given angle with respect to the scanning direction (the Y-axis direction in this embodiment) of the line sensor 20. Specifically, Figure 4 as well as Figure 5 As shown, in the rotating step S2, the workpiece 2 is rotated so that the angle formed by the scanning direction of the line sensor 20 and the direction repeated at the repetition pitch of the period Tb in the workpiece 2 is θ. In the present embodiment, the stage 10 on which the workpiece 2 is placed is rotated by the rotation drive mechanism 30, so that the workpiece 2 is tilted so that the angle formed by the b direction (the direction repeated at the repetition pitch of the period Tb) of the repeated structure of the workpiece 2 and the Y-axis direction is θ.

[0120] After the workpiece 2 is tilted in the rotation step S2, the imaging step S3 is performed. In the imaging step S3, based on the imaging conditions calculated in the calculation step S1, the line sensor 20 is scanned in the Y-axis direction (scanning direction) by the linear drive mechanism 40 to image the workpiece 2. In this case, in the imaging step S3, as shown in FIG. Figure 4 as well as Figure 5 As shown, the entire workpiece 2 is imaged by the line sensor 20 while the workpiece 2 is tilted at the angle θ calculated in the calculation step S1 .

[0121] Thus, in the imaging step S3, the workpiece 2 is imaged by scanning the line sensor 20 while the workpiece 2 is rotated by the rotation drive mechanism 30 and tilted at the angle θ calculated by the calculation unit 51. The image of the workpiece 2 captured by the imaging step S3 is sent to the image processing unit 53.

[0122] In the inspection step S4, based on the image of the workpiece 2 captured in the imaging step S3, the repeated structure in the workpiece 2 is inspected for defects. Specifically, based on the image of the workpiece 2 captured by the line sensor 20 in the imaging step S3, the repeated structure in the workpiece 2 is inspected. In this case, in the inspection step S4 of the present embodiment, the presence or absence of defects in the workpiece 2 is determined by performing a comparative inspection that compares pixels of two repeated structures in the captured image of the workpiece 2 acquired by scanning the line sensor 20 through the linear drive mechanism 40.

[0123] As described above, the specific determination of the presence or absence of defects in the workpiece 2 is performed by the image processing unit 53. That is, the image processing unit 53 performs image processing on the captured image to determine the presence or absence of defects in the repetitive structure of the workpiece 2.

[0124] In addition, the inspection step S4 may be performed after the imaging step S3 or simultaneously with the imaging step S3. That is, the image processing of the captured image may be performed after the line sensor 20 captures the entire workpiece 2 to determine whether the repeated structure of the workpiece 2 has defects, or the image processing of the captured image may be performed at any time while the line sensor 20 captures the workpiece 2 to determine whether the repeated structure of the workpiece 2 has defects.

[0125] As described above, it is possible to inspect defects in the repeated structure of the workpiece 2 .

[0126] Thus, according to the inspection device 1 and the inspection method involved in this embodiment, by tilting the workpiece 2 having a repetitive structure, θ (the inclination of the workpiece 2) and Ry (the resolution of the line sensor 20 in the Y-axis direction) are calculated based on Rx (the resolution of the line sensor 20 in the X-axis direction), Ta (the repetition period of the repetitive structure in the a-direction), and Tb (the repetition period of the repetitive structure in the b-direction), and the pixels of two repetitive structures in the camera image of the workpiece 2 acquired by scanning the line sensor 20 are compared, thereby inspecting defects of the workpiece 2.

[0127] Thus, since it is possible to perform imaging in the field of view direction of the line sensor 20 at a substantially integer ratio without changing the magnification of the imaging system, it is possible to inspect the repetitive structure of the workpiece 2 with high accuracy.

[0128] Furthermore, when the workpiece 2 is tilted, the repetitive pitch of the repetitive structure of the workpiece 2 changes simultaneously in the field of view direction and the scanning direction of the line sensor 20. Therefore, the repetitive pitches in the field of view direction and the scanning direction cannot be changed independently.

[0129] In this regard, in the inspection device 1 and the inspection method involved in the present embodiment, Ry is changed so that the period Tb is an integer period on the camera image of the workpiece 2, thereby calculating Ry and θ. That is, in the present embodiment, the scanning ARS is used to inspect the repeated structure of the workpiece 2. Thus, since the resolution Ry in the Y-axis direction as the scanning direction can be precisely adjusted, the degree of freedom of the combination of θ and Ry that satisfies the condition that the camera can be photographed in the field of view direction and the scanning direction of the line sensor 20 at an integer ratio can be increased. Therefore, by using the scanning ARS in combination, not only can the field of view direction of the line sensor 20 be photographed at a substantially integer ratio, but also the scanning direction of the line sensor 20 can be photographed at a substantially integer ratio. Therefore, the repeated structure of the workpiece 2 can be inspected further with high precision.

[0130] As described above, in the inspection device 1 and the inspection method in the present embodiment, Ry and θ are calculated by tilting the workpiece 2. However, in the actual workpiece 2, the repetition period Ta and Tb of the repetitive structure have various values ​​depending on the workpiece 2, and the reference resolution, that is, the resolution Rx, which is an input parameter, also has various values ​​depending on the inspection device 1. Therefore, there is a concern as to whether there are optimal θ and Ry for all Ta, Tb, and Rx. However, since it has been verified through simulation that the optimal θ and Ry can be calculated for all Ta, Tb, and Rx even if the workpiece 2 is tilted as described above, the results of the simulation are described below.

[0131] In this simulation, a rectangular chip with a side of 300 μm to 20,000 μm (0.3 mm to 20 mm) is assumed as the workpiece 2. That is, the chip size (workpiece size) is 300 μm to 20,000 μm on a side.

[0132] And, in Fig.10 , Fig.11 as well as Fig.12 2 shows the results of simulations when θ and Ry are calculated using the inspection method according to the above-described embodiment. Fig.10 The simulation results when using scanning ARS are shown. Fig.11 The simulation results are shown when scanning ARS is not used. Fig.12 The simulation results are shown when an area sensor is used instead of the line sensor 20 .

[0133] exist Figure 10 to Figure 12 In the example, the inspection method according to the above embodiment is used. Specifically, the example is a case where the workpiece 2 is tilted at an angle of θ and θ and Ry are calculated. The conventional example and the comparative example are cases where the inspection method according to the above embodiment is not used.

[0134] In addition, Figure 10 to Figure 12 In the above, the upper limit of the calculated θ is set to 1°, 2°, ..., 9°, 10°, and θ and Ry are calculated in each case, and the reference resolution Rx is set to 1.5μm, 3.0μm, 5.0μm, 10.0μm, 20.0μm, and θ and Ry are calculated in each case. In addition, the range of Ry is set to a maximum change of 10% in the direction of resolution improvement relative to the reference resolution Rx so that the inspection sensitivity does not decrease. In other words, Ry is changed within the range of 0.9×Rx≤Ry≤1.0×Rx.

[0135] In this simulation, θ changes at intervals of 0.001°, but it is not limited to this. θ can also change at intervals of 0.0005° or at intervals other than this. In addition, regarding Ry, when scanning ARS is used in combination ( Fig.10 ), Ry can be freely selected. On the other hand, when scanning ARS is not used ( Fig.11 ), Ry is changed to a value that can be selected in units of 0.1 μm. In addition, when an area sensor is used instead of a line sensor ( Fig.12 ), Rx=Ry.

[0136] And, in Figure 10 to Figure 12 In the example, when the optimal θ and Ry are selected, the residual error (offset) is displayed in white when it is less than 0.1 pixel, and the residual error (offset) is displayed in black when it is more than 0.1 pixel. If the residual error (offset) is less than 0.1 pixel, θ and Ry can be reliably calculated.

[0137] Fig.13 Yes Figure 10 to Figure 12 A table that is numerically summarized. Fig.13 In the Figure 10 to Figure 12 The residual error (offset) can be reduced to a ratio of less than 0.1 pixels (that is, the ratio of white). Fig.13 In the example, shading is performed when the ratio of the residual error (shift amount) being able to be made 0.1 pixel or less is 95.0% or more.

[0138] like Fig.13As shown, the case where the inspection method involved in the present embodiment is used ("Example") can make the proportion of residual errors (offsets) below 0.1 pixels higher than the case where the inspection method involved in the present embodiment is not used ("Comparative Example"). In addition, it can be seen that according to the inspection method involved in the present embodiment, θ and Ry can be fully calculated. Moreover, it can be seen that by using the scanning ARS in conjunction, even if it is limited to the range of θ≤3°, there are corresponding appropriate θ and Ry for almost all Rx, Ta, and Tb. In particular, by setting the upper limit of θ to 7° or more, it can be said that θ and Ry exist reliably. In addition, it can be seen that even if the scanning ARS is not used in conjunction, by setting the upper limit of θ to 6° or more, there are appropriate θ and Ry.

[0139] (Variation Example)

[0140] As mentioned above, although the inspection device, the inspection method, etc. which concern on this disclosure were demonstrated based on embodiment, this disclosure is not limited to the said embodiment.

[0141] For example, the present disclosure also includes methods obtained by implementing various modifications that a person skilled in the art would like to conceive of for the above-mentioned embodiments, and methods implemented by arbitrarily combining structural elements and functions in the embodiments within the scope that does not deviate from the main purpose of the present disclosure. In addition, the present disclosure also includes contents obtained by arbitrarily combining two or more technical solutions from among the multiple technical solutions recorded in the claims at the time of filing this application within the scope that is not technically contradictory. For example, when the cited technical solutions recorded in the claims at the time of filing this application are set as multiple cited technical solutions or multiple citations to multiple technical solutions, so that all of the upper technical solutions are cited within the scope that is not technically contradictory, the combination of all technical solutions included in the multiple cited technical solutions or multiple citations to multiple technical solutions is also included in the present disclosure.

[0142] In addition, the present disclosure can also be implemented as a program used in the inspection method according to the above-mentioned embodiment. For example, the present disclosure can be implemented as a program for causing a processor to execute the calculation step S1 in the inspection method.

[0143] Industrial Applicability

[0144] The technology disclosed in the present invention is useful as an inspection device and an inspection method for inspecting a workpiece having a repetitive structure.

Claims

1. An inspection device for inspecting a workpiece having a repeated structure repeatedly arranged in two orthogonal directions, the inspection device comprising: Carrier; A line sensor, the field of view direction of which is a first direction, for photographing the workpiece placed on the stage; A rotation drive mechanism that rotates the workpiece so as to form a given angle with a second direction that is orthogonal to the first direction; and a calculation unit for calculating the imaging conditions of the workpiece; If the resolution of the camera in the first direction of the inspection device is set to Rx, the resolution of the camera in the second direction of the inspection device is set to Ry, the given angle is set to θ, the repetition period of the repetitive structure in one of the two orthogonal directions in the workpiece is set to Ta, and the repetition period of the repetitive structure in the other of the two orthogonal directions in the workpiece is set to Tb, The calculation unit uses Rx, Ta and Tb as input parameters and calculates Ry and θ as the imaging conditions. The inspection device rotates the workpiece by the rotation drive mechanism so as to reach the angle θ calculated by the calculation unit, and scans the workpiece with the line sensor in a state where the workpiece is tilted to capture an image of the workpiece.

2. The inspection device according to claim 1, wherein: The inspection device inspects defects of the workpiece by comparing pixels of two of the repeated structures in a captured image of the workpiece acquired by scanning the line sensor.

3. The inspection device according to claim 2, wherein: If the two vectors of the repeated structure in the state before the workpiece is tilted at an angle of θ are set to (Xa, Ya), the two vectors of the repeated structure in the state after the workpiece is tilted at an angle of θ are set to (Xn, Yn), and the two vectors of the repeated structure on the camera image are set to (Xp, Yp), then Xp and Yp are expressed by the following formula: Xp=Xn / Rx=(Xa×cosθ-Ya×sinθ) / Rx, Yp=Yn / Ry=(Xa×sinθ+Ya×cosθ) / Ry, The calculation unit calculates θ and Ry so that Xp and Yp are integers.

4. The inspection device according to claim 3, wherein: The calculation unit changes Ry so that Yp becomes an integer period on the captured image, thereby calculating Ry and θ.

5. An inspection method for inspecting a workpiece having a repeated structure repeatedly arranged in two orthogonal directions, the inspection method comprising: A calculation process to calculate given imaging conditions; a rotating step of rotating and tilting the workpiece based on the imaging condition so as to form a given angle with a second direction orthogonal to the first direction; An imaging step of causing a line sensor having a field of view in the first direction to scan along the second direction to image the workpiece; and an inspection step of inspecting the repeated structure of the workpiece based on the image of the workpiece captured by the line sensor, If the resolution of the camera in the first direction is set to Rx, the resolution of the camera in the second direction is set to Ry, the given angle is set to θ, the repetition period of the repetitive structure in one of the two orthogonal directions in the workpiece is set to Ta, and the repetition period of the repetitive structure in the other of the two orthogonal directions in the workpiece is set to Tb, then in the calculation step, Rx, Ta and Tb are used as input parameters, and Ry and θ are calculated as the camera conditions. In the imaging step, the workpiece is imaged by scanning the line sensor in a state where the workpiece is tilted at the angle θ calculated in the calculation step.

6. The inspection method according to claim 5, wherein: In the inspection step, two pixels of the repetitive structure in the captured image of the workpiece are compared to inspect defects of the workpiece.

7. The inspection method according to claim 6, wherein: If the two vectors of the repeated structure in the state before the workpiece is tilted at an angle of θ are set to (Xa, Ya), the two vectors of the repeated structure in the state after the workpiece is tilted at an angle of θ are set to (Xn, Yn), and the two vectors of the repeated structure on the camera image are set to (Xp, Yp), then Xp and Yp are expressed by the following formula: Xp=Xn / Rx=(Xa×cosθ-Ya×sinθ) / Rx, Yp=Yn / Ry=(Xa×sinθ+Ya×cosθ) / Ry, In the calculation step, θ and Ry are calculated so that Xp and Yp are integers.

8. The inspection method according to claim 6 or 7, wherein: In the calculation step, Ry and θ are calculated by changing Ry so that Tb becomes an integer period on the captured image.

9. A recording medium recording a program used in an inspection method for inspecting a workpiece having a repeated structure repeatedly arranged in two orthogonal directions, The inspection method comprises: A calculation process to calculate given imaging conditions; a rotating step of rotating and tilting the workpiece based on the imaging condition so as to form a given angle with a second direction orthogonal to the first direction; An imaging step of causing a line sensor having a field of view in a first direction to scan along the second direction to image the workpiece; and an inspection step of inspecting the repeated structure of the workpiece based on the image of the workpiece captured by the line sensor, If the resolution of the camera in the first direction is set to Rx, the resolution of the camera in the second direction is set to Ry, the given angle is set to θ, the repetition period of the repetitive structure in one of the two orthogonal directions in the workpiece is set to Ta, and the repetition period of the repetitive structure in the other of the two orthogonal directions in the workpiece is set to Tb, then in the calculation step, Rx, Ta and Tb are used as input parameters, and Ry and θ are calculated as the camera conditions. In the imaging step, the workpiece is imaged by scanning the line sensor in a state where the workpiece is tilted at the angle θ calculated in the calculation step. The program is a program for causing a processor to execute the calculation step.

Images